Further evidence is reported indicating that magnesium sulfate administered before preterm birth may reduce the risk of cerebral palsy in offspring.
SAN FRANCISCO—The use of magnesium sulfate significantly reduced neonatal brain injury associated with maternal inflammation or maternal infection, according to research presented at the 31st Annual Meeting of the Society for Maternal-Fetal Medicine.
“We knew there were indications from other studies that magnesium sulfate might protect a preterm fetus from cerebral palsy, but we wanted to demonstrate direct and conclusive protective effect on the offspring brain in cases of maternal inflammation,” said study coauthor Ron Beloosesky, MD, of the Rambam Medical Center in Haifa, Israel. “We wanted to learn more about the protective effects of magnesium sulfate in cases where maternal inflammation causes preterm birth, so we used the very sensitive diffusion-tensor imaging, MRI, to study how magnesium sulfate works.”
Dr. Beloosesky and colleagues studied pregnant Sprague-Dawley rats at 18 days gestation that received i.p. lipopolysaccharide (LPS) (500 µg/kg) or saline at baseline. Dams were randomized to treatment with s.c. saline or magnesium sulfate (270 mg/kg loading followed by 27 mg/kg q20 min) for two hours prior to and following the i.p. LPS or saline. Pups were delivered spontaneously (e21) and allowed to mature until postnatal day 25. Female offspring (four to eight per group) were examined under isoflurane anesthesia with use of MRI and analyzed using voxel-based analysis after spatial normalization. T2 relaxation time was used to assess for white matter injury and diffusion-tensor imaging for fractional anisotropy comparison.
The results showed that offspring of LPS-treated dams exhibited significantly increased T2 levels, and reduced fractional anisotropy levels in white and gray matter (eg, corpus callosum, thalamus, hippocampus), consistent with diffuse cerebral injury. In contrast, offspring of magnesium sulfate–treated LPS dams demonstrated similar T2 and fractional anisotropy levels as controls in both white and gray matter.
The researchers concluded that magnesium sulfate treatment significantly reduced evidence of neonatal brain injury associated with maternal LPS. The findings suggest that maternal magnesium sulfate therapy may be most effective in human preterm deliveries associated with maternal/fetal inflammation.
“The next step,” said Dr. Beloosesky, “is to do more studies to understand exactly how the magnesium sulfate works and protects the fetal brain.”